Performance of phonemically targeted processing in conjunction with compression processing with spectral enhancement.

Abstract

The goal of the present study is to test, individually and in combination, two signal-processing strategies designed to improve both consonant and vowel perception. In the first strategy, specific consonants were targeted for processing to increase amplitude and duration. For consonants with a duration increase, the adjacent vowel was decreased proportionately in order to maintain overall word and sentence duration. Second, Coliga, an adaptive compression-processing strategy incorporating spectral enhancement, was used to process stimuli. Hearing-in-noise-test sentences were presented monaurally to normal-hearing and hearing-impaired adults in the presence of speech-shaped noise. For normal-hearing listeners, it appears that Coliga is improving intelligibility in certain conditions. Conservative amounts of duration and amplitude processing need to be applied in combination rather than when applied independently in order to provide benefit. For the hearing-impaired listeners, Coliga with spectral enhancement resulted in poorer performance than without, for all conditions except for the Coliga-only conditions, where the intelligibility was the same. It appears that phonemically-targeted speech processing and Coliga are working antagonistically due to either 1) the processing method negating the benefits when the two are combined, or 2) combining the duration and amplitude components leading to no benefit despite documented benefit of each when employed individually.